This document focuses on ATT System V Release 4 compliant Unices.
Introduction to Unix.
Unix is an operating system that is very powerful. It has been
around since the late 1960s, however it didn't begin to gain
popularity until the 1970's. It has and has had many of the
features that other companies are scrambling to incorporate into
their own OS.
Popular buzzwords today are "32-bit", "Multitasking",
"Multiprocessing", "Multiuser" and "Security". Unix has had all of
these features for many years. Companies such as Microsoft, Apple,
and IBM are trying to incorporate many of these features into their
OSs, however progress has been slow.
Brief history of Unix.
Unix was originally developed at ATT's Bell Labs. At the time ATT
did not realize this would be a marketable product and decided to
allow Universities access to the source code.
The University of California, Berkeley took this offer from ATT with
great enthusiasm and modified the source code to include additional
features not available on the original version from ATT. In fact,
the modifications were so extensive that the only two major versions
of Unix today are the ATT (System V) style and the BSD (Berkeley
Software Distribution) style.
Most companies of come up with a modification of their own and have
a version of Unix that is a combination of both styles. For
example, Sun's Sun OS 4.x is mostly BSD style, however their latest
release Sun OS 5.x is mostly ATT (System V) style.
Introduction to the file system.
The file system in Unix is very important. It is the users access
point to all of the programs online, external devices, and all files
for that matter.
Everything in Unix is a file. This is a very powerful tool for the
user, however it may be viewed as initially confusing, or difficult.
After learning the Unix file system the user will appreciate the
power of Unix and may be disappointed in the limitations imposed by
other simpler operating systems such as Windows 95 and Mac OS.
Commands for accessing the file system.
ls - list files
syntax: ls
List the files in a directory. The default is to list the files
in the current directory.
Common options
-a lists all files in the directory including hidden files (dot
files)
-l long listing which includes all file attributes
-F adds tags to the files which indicate the type of file
cd - change directory
syntax: cd
Change the present working directory.
mkdir - make directory
syntax: mkdir
Make a directory.
rmdir - remove directory
syntax: rmdir
Remove a directory.
rm - remove files
syntax: rm
Remove a file.
Common options
-r recursive remove
-f force removal regardless of permissions
cp - copy files
syntax: cp
Copy a file to a new file or different location.
Common options
-r recursive copy
mv - move files
syntax: mv
Move a file from one directory to another or rename a file.
ln - make link
syntax: ln
Create a file that is a link to another file.
Common options
-s make symbolic link
file - describe file
syntax: file
Describe the file.
Commands for reading files.
cat - print file contents
syntax: cat
Print the file contents without regards to file length or content.
more - print file contents page at a time
syntax: more
Print the file contents one page at a time.
less - print file contents page at a time
syntax: less
Print the file contents one page at a time, can also go in
reverse.
Commands for editing files.
ed - edit files
syntax: ed
Edit a file. Line editor. Very commonly found on all Unices.
vi - edit files
syntax: vi
Edit a file. Simple visual editor. Very commonly found on all
Unices.
emacs - edit files
syntax: emacs
Edit a file. Powerful text editor. Much more than just an
editor. Beyond the scope of this document. Type C-x C-c to quit
it.
Introduction to the Internet.
The Internet is a vast network of networked computers. It was very
common at the beginning of the Internet to have nothing but Unix
computers attached to it, however this is changing. Now many
different types of computers are attached. Still probably the most
common type of server on the Internet is a Unix computer.
Web sites, ftp sites and many other services are brought to the
general Internet community due to Unix computers.
Commands for accessing the Internet.
netscape - web browser
syntax: netscape
Popular web browser for accessing HTML pages. Found on many
different platforms (Unix, Mac, Windows).
ftp - file transfer protocol
syntax: ftp
Transfer files from one computer to another.
ncftp - feature-rich file transfer protocol
syntax: ncftp
Transfer files from one computer to another. Allows automatic
"anonymous" login to ftp sites.
telnet - access remote computers
syntax: telnet
Useful for accessing remote computers for many different purposes.
Once logged into the remote computer one can run any text-based
program inside of the telnet session. Many popular online games
can only be accessed via telnet.